forbid using '_' as a subqueue delimiter

Author: Florian Perucki

mrq/config.py

@@ -3,7 +3,7 @@
 import sys
 import re
 from .version import VERSION
-from .utils import get_local_ip
+from .utils import get_local_ip, DelimiterArgParser
 import atexit
 
 
@@ -344,7 +344,8 @@ def add_parser_args(parser, config_type):
         parser.add_argument(
             '--subqueues_delimiter',
             default='/',
-            help='Delimiter between main queue and subqueue names')
+            help='Delimiter between main queue and subqueue names',
+            action=DelimiterArgParser)
 
         parser.add_argument(
             '--admin_port',

mrq/utils.py

@@ -4,6 +4,7 @@
 import math
 import json
 import datetime
+import argparse
 from collections import deque
 from bson import ObjectId
 
@@ -194,3 +195,11 @@ def next(self, val):
         self.__sum += val
         self.__q.append(val)
         return 1.0 * self.__sum / len(self.__q)
+
+
+class DelimiterArgParser(argparse.Action):
+    def __call__(self, parser, namespace, value, option_string):
+        if value == '_':
+            parser.error("Cannot use '%s' as a subqueue delimiter" % value)
+
+        setattr(namespace, self.dest, value)